<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            height: 500px;
            width:  500px;
            display: inline-block;
            background-color: aqua;
        }
        #a{
            margin-bottom: 20px;

        }
        #b{
            margin-top: 30px;
    
        }

    </style>
</head>
<body>
    <div>
        <div id="a"></div>
        <div id="b"></div>
        </div>
    
    
</body>
</html>